Reply
 
Thread Tools Display Modes
 
Old 03-14-2015, 11:15 PM   #1
New Member
 
Join Date: Dec 2014
Posts: 7
Year: 1980
Coachwork: Gillig
Engine: Cat
Onan Installation Tutorial

Hi all, I'm about to jam a 1981, 6.5kw Gas powered Onan RV generator in my 1981 Gillig. My most important questions for now are electrical.

Doodad power - There are four colored wires coming out of what I will call the "control box." They are blue, red, green and orange. I assume these are for remote start and hour counter and such. Can anyone remove my assumption?

Main power - I have a 120/240 genny. Can anyone identify my main power lines? (The wires in the shielded housing that lead into the RV to turn on the lights and AC.)

Mounting - anyone ever cram one of these in a Gillig? Rear, left bay is home, just before the tire. I'm thinking of angle steel (what size?) and I'd like part of the cradle hung on the main frame. Any thoughts?

Tanks - I was thinking a 15 gallon, aluminum baja tank for fuel storage. Any thoughts?

Resources - Anyone know where I can find info to look this stuff up myself? I found some PDF owners manuals on line but all are general or for newer Onans.

Locals - Anyone in Utah Valley, Utah and want to hold my hand through this?

Side note - This power plant doesn't idle. I'll begin the hunt for the culprit tomorrow. Start with fuel pump and carb.

Thanks a lot!
David Allaband is offline   Reply With Quote
Old 03-15-2015, 08:53 AM   #2
Bus Nut
 
Join Date: Aug 2010
Posts: 332
Year: 1995
Coachwork: Thomas
Chassis: International
Engine: 466DT
Rated Cap: 65
Any info you need on the onan, I would go here.

Onan Generators - SmokStak

Just read up on their "stickies", before asking questions. You need to know your serial and model number. The guys on there will tell you about anything you need to know about the onan.

I know nothing on gilligs, sorry.
Hvbuzz is offline   Reply With Quote
Old 03-27-2015, 08:55 PM   #3
Bus Crazy
 
Join Date: Jan 2008
Location: Upstate NY (Mohawk Valley)
Posts: 1,096
Quote:
Originally Posted by David Allaband
. . . Side note - This power plant doesn't idle. I'll begin the hunt for the culprit tomorrow. Start with fuel pump and carb.

Thanks a lot!
Do you mean that it runs under load, but stalls when the load is removed, or do you mean it fires up, and quits right away?

The old Onans had 3-wire control, hold start to common until it is running, hold stop to common until the last "chug" when you want to stop it. Once it develops oil pressure, an oil pressure switch activates a "run" relay that drops out the starter and keeps the ignition powered.

Controls on newer generators are 2-wire. Hold them together for as long as you want the generator to run, the engine stops when you release them.

I can't help you with the fourth wire, but with 3-wire control, there should be a spring loaded 3-position toggle switch with start and stop wires on the genset. You can duplicate the connection to this switch to remote push-buttons.

If the oil pressure switch is bad, the generator might start but will shut down when you release the "start" switch. And the starter will not stop turning until you do.

Some people try to make a 3-wire generator work on 2-wire control using an SPDT relay. The relay holds "start" forever when energized for a request-to-run, and holds "stop" forever when the run request is released.

A little-known fact I discovered is that if you have such a relay holding the "stop" button down, and you use the start switch on the generator, when there is no oil pressure the generator will ignore the "stop" and turn over the generator. As soon as there is pressure, the "run" relay controlled by the oil pressure will release the starter, look at the "stop" command and shut back down. It will do this start/stop for as long as both "buttons" are held down.

This may not be your problem, but I hope this helps you understand the older gensets. We had a professional Cummins/Onan mechanic condemn one of our old gensets because he "couldn't get the oil pressure relay to work." Years later when I discovered the start/stop issue, I'll bet he was being "Bit by the bear" trying the local start switch while a stop command was being held by the remote 2-wire to 3-wire relay in the control panel in the next room.

Good luck!
__________________
Someone said "Making good decisions comes from experience, experience comes from bad decisions." I say there are three kinds of people: those who learn from their mistakes, those who learn from the mistakes of others, and those who never learn.
Redbear is offline   Reply With Quote
Old 03-27-2015, 11:02 PM   #4
Bus Nut
 
Join Date: Sep 2014
Posts: 546
If you have an MCCK: http://www.cumminsonan.com/www/pdf/manuals/927-0121.pdf

I have a 70's era 4kw Onan hanging under the WC door area. I am using a 10g spun al. buggy tank in the same area filled through the open WC lift door via a hatch in the floor. My Onan has a large steel platform that I hung with 4 -3/8" all thread and secured from moving around. I have a remote start in the bus, no hr. meter. Run time's about 20 hours with that tank.

There are some pics in my build thread: http://www.skoolie.net/forums/f27/2-...uild-9706.html
dond is offline   Reply With Quote
Old 04-22-2015, 11:14 PM   #5
New Member
 
Join Date: Dec 2014
Posts: 7
Year: 1980
Coachwork: Gillig
Engine: Cat
Thanks for the help everyone. The forum smokstak.com was a great resource. I found an antique Onan forum and someone sent me all the repair, operation and installation manuals within one day!
David Allaband is offline   Reply With Quote
Old 04-23-2015, 11:40 AM   #6
Bus Nut
 
Join Date: Aug 2010
Posts: 332
Year: 1995
Coachwork: Thomas
Chassis: International
Engine: 466DT
Rated Cap: 65
Glad smokstak worked out.

I don't have my onan mounted under the bus yet. But I'm planning on using the same brackets and set up as the yamaha I had under there. Here is a pic.

Untitled by Hvbuzz, on Flickr

Those big angle pieces are off any medium duty truck. It's the brackets for the fuel tanks. Should be common in any junk yard. Not sure if they would work for you, but they sure are easy to work with, and I know it will hold the weight of the big old onan's easy.
Hvbuzz is offline   Reply With Quote
Old 04-25-2015, 06:39 PM   #7
Bus Nut
 
Join Date: Sep 2014
Posts: 546
My 4K Onan is 217 lbs.
dond is offline   Reply With Quote
Old 04-25-2015, 07:47 PM   #8
Skoolie
 
Join Date: Mar 2015
Posts: 231
Quote:
Originally Posted by David Allaband View Post
Thanks for the help everyone. The forum smokstak.com was a great resource. I found an antique Onan forum and someone sent me all the repair, operation and installation manuals within one day!
yea a great bunch of folks over there !!!
they have helped me with a lot of shall we say older? equipment
c_hasbeen is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Virginia Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 04:05 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.